The rating voltage of a gas discharging lamp is generally 80V-150V, but the current voltage supply is 220V. For proper use, one should decrease the current supply from 220V to about 80V-150V. Simultaneously, the bulb is provided with a step down, current limiting, and protective device of equivalent power. An inductive, low frequency choke is the most commonly adopted for these purposes. Such a low frequency choke occupies a large volume and is heavy. It also exhibits high loss, low power factor, high noise and strong interference, and low illumination quality; and its voltage, current, and power are difficult to control.
Chinese Patent No. 98218196.5 teaches an adaptive controller for a high intensity gas discharging lamp, which achieves light changes by adjusting inductance coil and inductive capacity. Like conventional inductance performance in regards to energy consumption, noise, power factor, voltage, current, and start-up, the adaptive controller consumes large amounts of energy and exhibits strong interference, and its power, voltage, and current are likely to be affected by circuitry voltage fluctuation. Therefore, the adaptive controller is not generally well-suited for application in a high-power gas discharging lamp.
Chinese Patent No. 01264335.1 teaches, however, a high power-factor electronic ballast for controlling a high-power gas discharging lamp, which provides an electronic ballast that can increase the power factor of the discharging lamp and is, therefore, energy saving and low-cost. Such an electronic ballast provides high quality lighting, and has a long service life, but does not work effectively if the power of the lamp is high. Because of the insufficiency of the pulse time and pulse amplitude, if there is exterior voltage fluctuation, the lamp is difficult to start up, or even be lighted. In the absence of a high-power, start-up trigger lighting circuit, the electronic ballast is not suitable for use in a high-power gas discharging lamp because of its poor stability and low reliability.